Some embodiments relate to semiconductor power devices and methods of manufacturing such devices, such as in the context of a power device capable of switching relatively high currents and/or at relatively high voltages. Such currents may be in the order of one to hundreds of Ampere and such voltages may be in the order of a few hundreds to thousands of Volts.
Published US patent application US2004/207968A1, which is incorporated herein by reference, discloses a power switching module that has several power switches. Each one of power switch includes a first substrate and a second substrate that both have several electrically conductive areas for conducting currents and providing signals on at least one of their surfaces. Insulated gate bipolar transistors are provided on the electrically conductive areas of the first substrate. One side of these transistors is a collector of the transistor and the collector is directly coupled to the electrically conductive areas of the first substrate. An opposite side of these transistors includes an emitter and a gate. Interconnect structures formed by electrically conductive cylinders are provided between emitters and gates, and specific electrically conductive areas of the second substrate.
As shown in FIG. 3 of the cited patent application and as described in its description, an electrically conductive area 64 of the second substrate 60, which is the electrically conductive area 64 to which the emitters are coupled, is relatively large because it has to conduct relatively large currents. However, because the gates have to receive a signal as well, separate electrically conductive areas (not numbered in FIG. 3 of the cited patent application) are manufactured inside the electrically conductive areas. The separate electrically conductive areas are isolated from the electrically conductive area 64 by means of a relatively large gap in between the electrically conductive areas. In practical embodiments, as a result of manufacturing characteristics, gaps are 1 millimeter wide—the layer in which the separate electrically conductive areas are present are relatively thick to be able to conduct high currents and, consequently, the gaps that have to be manufactured between electrically conductive area 64 and the separate electrically conductive area is relatively wide as well.